Glycosaminoglycan glucosamine

Proteolytic digestion of proteoglycans liberates the carbohydrate side-chains, which are known as glycosaminoglycans (also known as mucopolysaccharides). All the glycosaminogly-cans contain derivatives of glucosamine or galactosamine. Six major groups are known, one of which is heparin. 

Endogenous glucosamine is used for the production of glycosaminoglycans and other proteoglycans in articular cartilage. 

Figure 2. Structures of the glycosaminoglycans and their linkage regions to protein. Two disaccharide repeating units are shown to emphasize the microheterogeneity that exists in some cases. Heparan sulfate and heparin show many structural similarities. However, heparan sulfate contains more GlcNAc(a-1 — 4)GlcUA repeating units fewer glucosamine residues are N-sulfated, and few iduronic acid residues are sulfated at C2.

The PhEur 2005 describes sodium hyaluronate as the sodium salt of hyaluronic acid, a glycosaminoglycan consisting of D-glucuronic acid and N-acetyl-o-glucosamine disaccharide imits. 

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